1,254 research outputs found

    Human Rating the Orion Parachute System

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    Human rating begins with design. Converging on the requirements and identifying the risks as early as possible in the design process is essential. Understanding of the interaction between the recovery system and the spacecraft will in large part dictate the achievable reliability of the final design. Component and complete system full-scale flight testing is critical to assure a realistic evaluation of the performance and reliability of the parachute system. However, because testing is so often difficult and expensive, comprehensive analysis of test results and correlation to accurate modeling completes the human rating process. The National Aeronautics and Space Administration (NASA) Orion program uses parachutes to stabilize and decelerate the Crew Exploration Vehicle (CEV) spacecraft during subsonic flight in order to deliver a safe water landing. This paper describes the approach that CEV Parachute Assembly System (CPAS) will take to human rate the parachute recovery system for the CEV

    MONITORING RACCOON RABIES IN ALABAMA: THE POTENTIAL EFFECTS OF HABITAT AND DEMOGRAPHICS

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    Abstract: Density, morphometrics, and disease prevalence of raccoon populations were determined in 4 habitats (agriculture, riverine, managed, and forested) in central Alabama. In addition we monitored 71 collared raccoons to determine survival. Density estimates were similar in the agriculture (ag) and riverine habitats in central Alabama with 8 raccoons/km 2 , and lower in the forested habitat at 5 raccoons/ km 2 . Retention of juveniles did not appear to contribute to observed higher populations in the riverine and ag habitat. Although the riverine and ag, possibly due to supplemental resources, likely provide better habitat for raccoons, we found only body size in female raccoons to be different across habitats (P = 0.001). Humancaused mortality (either hunting or missing and presumed killed) was the main cause of mortality in several raccoon populations during fall; however, fall survival did not differ between the habitats (χ = 1.47, d.f. = 3, P = 0.69). Although rabies and distemper virus were prevalent in all habitats, they did not appear to contribute to mortality even with a high proportion of the population exhibiting positive CDV titers (ag -44%, managed-50%) and rabies titers (managed-57% and riverine habitat-60%)

    Complete Columbian mammoth mitogenome suggests interbreeding with woolly mammoths

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    Abstract Background Late Pleistocene North America hosted at least two divergent and ecologically distinct species of mammoth: the periglacial woolly mammoth (Mammuthus primigenius) and the subglacial Columbian mammoth (Mammuthus columbi). To date, mammoth genetic research has been entirely restricted to woolly mammoths, rendering their genetic evolution difficult to contextualize within broader Pleistocene paleoecology and biogeography. Here, we take an interspecific approach to clarifying mammoth phylogeny by targeting Columbian mammoth remains for mitogenomic sequencing. Results We sequenced the first complete mitochondrial genome of a classic Columbian mammoth, as well as the first complete mitochondrial genome of a North American woolly mammoth. Somewhat contrary to conventional paleontological models, which posit that the two species were highly divergent, the M. columbi mitogenome we obtained falls securely within a subclade of endemic North American M. primigenius. Conclusions Though limited, our data suggest that the two species interbred at some point in their evolutionary histories. One potential explanation is that woolly mammoth haplotypes entered Columbian mammoth populations via introgression at subglacial ecotones, a scenario with compelling parallels in extant elephants and consistent with certain regional paleontological observations. This highlights the need for multi-genomic data to sufficiently characterize mammoth evolutionary history. Our results demonstrate that the use of next-generation sequencing technologies holds promise in obtaining such data, even from non-cave, non-permafrost Pleistocene depositional contexts.http://deepblue.lib.umich.edu/bitstream/2027.42/112426/1/13059_2011_Article_2544.pd

    What is a good medical decision? A research agenda guided by perspectives from multiple stakeholders

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    Informed and shared decision making are critical aspects of patient-centered care, which has contributed to an emphasis on decision support interventions to promote good medical decision making. However, researchers and healthcare providers have not reached a consensus on what defines a good decision, nor how to evaluate it. This position paper, informed by conference sessions featuring diverse stakeholders held at the 2015 Society of Behavioral Medicine and Society for Medical Decision Making annual meetings, describes key concepts that influence the decision making process itself and that may change what it means to make a good decision: interpersonal factors, structural constraints, affective influences, and values clarification methods. This paper also proposes specific research questions within each of these priority areas, with the goal of moving medical decision making research to a more comprehensive definition of a good medical decision, and enhancing the ability to measure and improve the decision making process

    Lyssavirus Vaccine with a Chimeric Glycoprotein Protects across Phylogroups

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    Rabies is nearly 100% lethal in the absence of treatment, killing an estimated 59,000 people annually. Vaccines and biologics are highly efficacious when administered properly. Sixteen rabies-related viruses (lyssaviruses) are similarly lethal, but some are divergent enough to evade protection from current vaccines and biologics, which are based only on the classical rabies virus (RABV). Here we present the development and characterization of LyssaVax, a vaccine featuring a structurally designed, functional chimeric glycoprotein (G) containing immunologically important domains from both RABV G and the highly divergent Mokola virus (MOKV) G. LyssaVax elicits high titers of antibodies specific to both RABV and MOKV Gs in mice. Immune sera also neutralize a range of wild-type lyssaviruses across the major phylogroups. LyssaVax-immunized mice are protected against challenge with recombinant RABV and MOKV. Altogether, LyssaVax demonstrates the utility of structural modeling in vaccine design and constitutes a broadened lyssavirus vaccine candidate

    Parenting around child snacking: development of a theoretically-guided, empirically informed conceptual model

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    BackgroundSnacking contributes to excessive energy intakes in children. Yet factors shaping child snacking are virtually unstudied. This study examines food parenting practices specific to child snacking among low-income caregivers.MethodsSemi-structured interviews were conducted in English or Spanish with 60 low-income caregivers of preschool-aged children (18 non-Hispanic white, 22 African American/Black, 20 Hispanic; 92% mothers). A structured interview guide was used to solicit caregivers’ definitions of snacking and strategies they use to decide what, when and how much snack their child eats. Interviews were audio-recorded, transcribed verbatim and analyzed using an iterative theory-based and grounded approach. A conceptual model of food parenting specific to child snacking was developed to summarize the findings and inform future research.ResultsCaregivers’ descriptions of food parenting practices specific to child snacking were consistent with previous models of food parenting developed based on expert opinion [1, 2]. A few noteworthy differences however emerged. More than half of participants mentioned permissive feeding approaches (e.g., my child is the boss when it comes to snacks). As a result, permissive feeding was included as a higher order feeding dimension in the resulting model. In addition, a number of novel feeding approaches specific to child snacking emerged including child-centered provision of snacks (i.e., responding to a child’s hunger cues when making decisions about snacks), parent unilateral decision making (i.e., making decisions about a child’s snacks without any input from the child), and excessive monitoring of snacks (i.e., monitoring all snacks provided to and consumed by the child). The resulting conceptual model includes four higher order feeding dimensions including autonomy support, coercive control, structure and permissiveness and 20 sub-dimensions. Conclusions: This study formulates a language around food parenting practices specific to child snacking, identifies dominant constructs, and proposes a conceptual framework to guide future research

    SEMA4D compromises blood–brain barrier, activates microglia, and inhibits remyelination in neurodegenerative disease

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    AbstractMultiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by immune cell infiltration of CNS, blood–brain barrier (BBB) breakdown, localized myelin destruction, and progressive neuronal degeneration. There exists a significant need to identify novel therapeutic targets and strategies that effectively and safely disrupt and even reverse disease pathophysiology. Signaling cascades initiated by semaphorin 4D (SEMA4D) induce glial activation, neuronal process collapse, inhibit migration and differentiation of oligodendrocyte precursor cells (OPCs), and disrupt endothelial tight junctions forming the BBB. To target SEMA4D, we generated a monoclonal antibody that recognizes mouse, rat, monkey and human SEMA4D with high affinity and blocks interaction between SEMA4D and its cognate receptors. In vitro, anti-SEMA4D reverses the inhibitory effects of recombinant SEMA4D on OPC survival and differentiation. In vivo, anti-SEMA4D significantly attenuates experimental autoimmune encephalomyelitis in multiple rodent models by preserving BBB integrity and axonal myelination and can be shown to promote migration of OPC to the site of lesions and improve myelin status following chemically-induced demyelination. Our study underscores SEMA4D as a key factor in CNS disease and supports the further development of antibody-based inhibition of SEMA4D as a novel therapeutic strategy for MS and other neurologic diseases with evidence of demyelination and/or compromise to the neurovascular unit
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